<?php

namespace cx_newsletter;

abstract class database_item 
implements database_item_interface {
    public function __construct(?int $id = null) {
        $this->id = $id;
    }

    public function has_id() : bool {
        return $this->id !== null;
    }

    public function get_id() : int {
        if (!$this->has_id()) {
            $exception = "\n\n";
            $exception .= 'Database item which ID trying to be loaded, has ';
            $exception .= 'no ID. That mean it could not exists, in the ';
            $exception .= 'database, because only items which not exists in ';
            $exception .= 'the database has not own ID.';
            $exception .= "\n\n";

            throw new \exception($exception);
        }
        
        return $this->id;
    }


    private ?int $id;
}